Will an Active PFC power suppy reduce your power bill?

[blueroomelectronics]

Will upgrading an older ATX PC power supply to a modern Active PFC 80 Plus supply make a noticeable impact on your electricity bill?

Does the overall wattage rating affect efficiency?

I was reading this interesting article on the new Intel Atom 330 micro-atx motherboard I'd like to use as a home server. (compared to a Cray XP in the article)
Dual Core Atom: Intel D945GCLF2 & Atom 330 Review - Page 15 - Power Consumption & Conclusion

 

[Nigel Goodwin]

I wouldn't have thought so, as far as I'm aware it doesn't affect your metering in any way.

 

[blueroomelectronics]

Then why do they sell for more? Why should I want Active vs Passive PFC?

I did find this calculator on 80 Plus.
**broken link removed**

 

[Nigel Goodwin]

Then why do they sell for more? Why should I want Active vs Passive PFC?

Probably for commercial use? - poor PFC is very expensive for industrial users.

Or it may be like hydrogen making schemes - if you sell it, then enough idiots will buy it

 

[Ubergeek63]

Unless you have a very new meter it does not save you a nickel even though it saves the power company oodles.

On the other hand a brand spanking new supply will likely be energy star compliant and be more efficient when the computer is not busy. The old 95% switchers were only 95% at full load, the new regs require them to be efficient at low load and hang a max draw at no load on them as well.

Dan

 

[crutschow]

Power factor correction is required by the power company's need to reduce harmonic and reactive line currents. It likely will have little, if any effect on your power bill, since the power company doesn't charge you for reactive current (except for the IR loss in your house wiring from the reactive currents which is likely very small).

 

[BuffaloEngineer]

I think (not an expert!) that you would not save any money - your bill is based on the number of watts going through the meter, not on the reactive or resistive nature of the power being used.

From what I've read about PFC, it's required on devices to reduce transient loads on the power lines - it benefits the power company, but not the user.

 

[blueroomelectronics]

Perhaps the power company should subsidize Active PFC supplies.

 

[crutschow]

Perhaps the power company should subsidize Active PFC supplies.

Good luck with that.

 

[audioguru]

Industrial power meters' measurements include the reactive power because it is huge.
The reactive power in a home is too low for them to bother measuring.

Don't pay the Chinese guy a fortune for his simple capacitor (for power factor correction) that does not affect your home's power measurement. The Chinese guy is a liar or maybe homes in China are charged extra for reactive power.

 

[Ubergeek63]

Industrial power meters' measurements include the reactive power because it is huge.
The reactive power in a home is too low for them to bother measuring.

Don't pay the Chinese guy a fortune for his simple capacitor (for power factor correction) that does not affect your home's power measurement. The Chinese guy is a liar or maybe homes in China are charged extra for reactive power.

Actually they would love to charge you for reactive power.

If they could they would charge you for the RMS voltage times the RMS current divided by the power factor since that is what they actually have to supply.

An ideal 500µF cap directly across the US power line will draw 22A, blow the breakers in your house, and load down the generators with a PF of 0.00 but will not touch your power meter.

The fact of the matter is that until recently, it simply cost to much to harass residences. That is changes now as remote readable digital meters are available and actually cost less than the old mechanical ones.

Dan